In situ location of effector and memory CD8 T cells (B137)

Abstract

Abstract CD8 T cells are critical for the clearance of intracellular pathogens. Following viral infection, naïve CD8 T cells differentiate into effector cells that target and eliminate infected cells. Upon viral clearance, a majority of effector cells die, while a small fraction survives to establish a memory population. Upon future exposures to the same pathogen, these memory T cells are able to rapidly respond and efficiently eliminate the infection. Although much is known about the activation and differentiation of CD8 T cells, the precise in situ location of effector and memory CD8 T cells is not well characterized. Here we present an in situ analysis of the localization of effector and memory CD8 T cells during the murine immune response to acute infection with LCMV. We utilized a transgenic mouse model system in which effector and memory CD8 T cells are irreversibly tagged with yellow fluorescent protein (YFP). We tracked YFP-positive effector and memory CD8 T cells in relation to LCMV-infected cells. Following LCMV infection, activated CD8 T cells were first observed within the T cell zones. As the immune response progressed, effector CD8 T cells migrated to the red pulp regions. Upon viral clearance, memory CD8 T cells localized to the T cells zones. Interestingly, CD44hi memory-phenotype CD8 T cells in naïve mice exhibited identical in situ localization as the memory CD8 T cells observed following LCMV infection.